<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .pie,
        .pie::before {
            display: inline-block;
            width: 0;
            border-radius: 50%;
            font-size: 0;
        }

        .pie span {
            font-size: 1rem;
            position: absolute;
            color: #fff;
            transform: translate(-50%, -50%) rotate(-45deg);
        }

        .pie {
            position: relative;
            border: solid 75px;
            border-color: #3c7 #3c7 #37c #37c;
            box-sizing: border-box;
            transform: rotate(45deg);
        }

        .pie::before {
            content: '';
            position: absolute;
            border: solid 75px;
            border-color: #37c #37c transparent transparent;
            transform: translate(-50%, -50%) rotate(.0turn);
            animation: spine 10s linear infinite,
                convex 10s step-end infinite;
            animation-play-state: paused;
            animation-delay: inherit;
        }

        @keyframes spine {
            to {
                transform: translate(-50%, -50%) rotate(1turn);
            }
        }

        @keyframes convex {
            50% {
                border-color: transparent transparent #3c7 #3c7;
            }
        }
    </style>
</head>

<body>
    <div class="pie" style="animation-delay: -1s;"><span>10%</span></div>
    <div class="pie" style="animation-delay: -2.5s;"><span>25%</span></div>
    <div class="pie" style="animation-delay: -5s;"><span>50%</span></div>
    <div class="pie" style="animation-delay: -8s;"><span>80%</span></div>
</body>

</html>